1. Field of the Invention
The present invention relates to a network transmission equipment, more particularly to a repeater complying the IEEE 1394 and Ethernet protocols.
2. Description of the Related Art
The IEEE 1394 is a protocol provides a maximum rate of 400 Mbps and a maximum transmission distance of 100 m in realtime. The broadcasting data and anisotropy data such as Internet data can be transmitted simultaneously in this protocol. Recently, the IEEE 1394 tends to prevail even in field of Internet data transmission because it is possible to transmit Internet Protocol (IP) data through IEEE 1394 LLC and PHY instead of Ethernet link layers, based on the use of the internet protocol (IP)-over-1394 technique. In the IEEE 1394, however, the repeaters are required for extending the transmission distance, as the IEEE 1394 has a limited standard 4.5 m transmission distance or range.
The repeater is not an internetworking equipment because the repeater operates in a physical layer of OSI reference model and substantially extends the segments of individual networks. Therefore, cables connected by the repeater are regarded as being a part of the same physical network. The repeater, which does not drive any software, only amplifies initial signals without affecting any traffic of the network.
FIGS. 1a and 1b illustrate the structures of an Ethernet repeater and an IEEE 1394 repeater according to the prior art.
Referring to FIG. 1a, the conventional Ethernet repeater allows not only the transmission distance to be extended but also increase the numbers of transmission port in order to effectively transmit Ethernet data. In the conventional Ethernet repeater, an unshielded twisted pair (UTP) cat. 5/5E is used for a transmission through which the Ethernet data is input to an input interface 101.
In operation, an input interface 101 sends incoming Ethernet data to a first converter 102 in which the Ethernet data are transferred to an Ethernet physical element 103. Then, an Ethernet physical element 103 performs modulation/demodulation processes of the Ethernet data to be transmitted. The processed Ethernet data are transmitted to an output interface 105 via a second converter 104. Finally, the output interface 105 transmits the Ethernet data through the UTP cat. 5/5 E. In this case, the transmission rates of the Ethernet data may be, for example, 10/100 Mbps and 1 Gbps. The transmission distances may be, for example, 100 mm, when the UTP is used for the transmission media.
In the conventional Ethernet repeater, if the abnormal voltage is inadvertently applied to the transmission media, the internal chips such as the Ethernet physical element 103, etc. may be damaged. The first converter 102 and the second converter 104 can isolate the Ethernet physical element 103, etc. from the transmission media, if necessary, in order to prevent possible damage caused by the abnormal voltage.
Referring to FIG. 1b, the conventional IEEE 1394 repeater also allows not only the transmission distance to be extended but also the number of the transmission ports to be increased in order to effectively transmit the IEEE 1394 data. Here, an unshielded twisted pair (UTP) cat. 5/5E is used as a transmission media through which the IEEE 1394 data is input to an input interface 101. The input interface 101 sends the received IEEE 1394 data to the first converter 102 in which the IEEE 1394 data are transferred to an IEEE 1394 physical unit 204. Then, the IEEE 1394 physical unit 204 performs modulation/demodulation processes of the IEEE 1394 data to be transmitted. The processed IEEE 1394 data are sent to the output interface 105 via the second converter 104. Finally, the output interface 105 transmits the IEEE 1394 data through the UTP cat. 5/5 E. In this case, the transmission rates of the IEEE 1394 data may be, for example, 100 Mbps 200 Mbps, 400 Mbps, 800 Mbps and 3.2 Gbps. The transmission distance may be, for example, 100 mm, when the UTP is used for the transmission media.
Similarly in the conventional IEEE 1394 repeater shown in FIG. 1b, if the abnormal voltage is applied to the transmission media, the internal chips such as the IEEE 1394 physical unit 204, etc. may be damaged. The first converter 102 and the second converter 104 can isolate the IEEE 1394 physical unit 204, etc. from the transmission media, if necessary, in order to prevent possible damage caused by the abnormal voltage.
The IEEE 1394 physical unit 204 further includes a first level converter 106, a second level converter 108, and an IEEE 1394 physical element 107. The modulation and the demodulation processes are basic performances of the IEEE 1394 physical unit 204. To this end, the first level converter 106 and the second level converter 108 changes signal voltage levels based on the variation of the transmission media. Specifically, the IEEE 1394 may use STP, UTP, or Optical fiber as its transmission media. The input signals, which input and output to and from the physical element, vary in the signal voltage level in accordance with the transmission media types. The signal voltage levels of the STP and the optical fiber are not identical to that of the UTP. Generally, the IEEE physical element 107 uses a signal voltage for the STP and the optical fiber. Therefore, if UTP is used for the IEEE physical element 107, then it is required to change the used signal voltage level. For this operation, the first level converter 106 and the second level converter 108 are necessary to convert or change the input signal voltage level.
As shown in FIGS. 1a and 1b, both the Ethernet repeater and the IEEE 1394 repeater use the UTP cat. 5 as the transmission media. Recently, an apparatus having both an Ethernet LAN card and an IEEE 1394 card mounted therein has been commercially available and becoming popular. In this environment, the user must use both the Ethernet repeater and the IEEE 1394 repeater separated from each other. Therefore, the conventional repeaters have drawbacks in that the Ethernet repeater and the IEEE 1394 repeater, which are separated with each other, takes too much space and the cost is high. Accordingly, there has been demand for a technique of combining both the Ethernet repeater and the IEEE 1394 repeater together and a technique of converting the transmission data protocol to the proper output protocol through the repeater by using the conversion functions of the Ethernet and IEEE 1394 protocols.